PostHog · marandaneto · Mar 25, 2026
@@ -188,6 +188,7 @@
 		DA4AF6292D119FCD0053EA38 /* PostHog.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 3AC745B5296D6FE60025C109 /* PostHog.framework */; };
 		DA4AF62A2D119FCD0053EA38 /* PostHog.framework in Embed Frameworks */ = {isa = PBXBuildFile; fileRef = 3AC745B5296D6FE60025C109 /* PostHog.framework */; settings = {ATTRIBUTES = (CodeSignOnCopy, RemoveHeadersOnCopy, ); }; };
 		DA4FFB152DA93C78006BAEEA /* PostHogSessionReplayTest.swift in Sources */ = {isa = PBXBuildFile; fileRef = DA4FFB142DA93C78006BAEEA /* PostHogSessionReplayTest.swift */; };
+		ARPERF0004000000000004 /* PostHogGraphicsImageRenderer.swift in Sources */ = {isa = PBXBuildFile; fileRef = ARPERF0003000000000003 /* PostHogGraphicsImageRenderer.swift */; };
 		DA4FFBB52DAD5B01006BAEEA /* PostHogIdentityTests.swift in Sources */ = {isa = PBXBuildFile; fileRef = DA4FFBB42DAD5AF9006BAEEA /* PostHogIdentityTests.swift */; };
 		DA52CACB2F24027500305F3D /* PostHogMulticastCallback.swift in Sources */ = {isa = PBXBuildFile; fileRef = DA52CACA2F24027500305F3D /* PostHogMulticastCallback.swift */; };
 		DA52CAD32F2402E000305F3D /* PostHogMulticastCallbackTest.swift in Sources */ = {isa = PBXBuildFile; fileRef = DA52CAD22F2402E000305F3D /* PostHogMulticastCallbackTest.swift */; };
@@ -746,6 +747,7 @@
 		DA3BB4DE2ED992780097A97A /* PostHogDebugImageProvider.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PostHogDebugImageProvider.swift; sourceTree = "<group>"; };
 		DA3BB5042EDF15320097A97A /* PostHogStackFrame.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PostHogStackFrame.swift; sourceTree = "<group>"; };
 		DA4FFB142DA93C78006BAEEA /* PostHogSessionReplayTest.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PostHogSessionReplayTest.swift; sourceTree = "<group>"; };
+		ARPERF0003000000000003 /* PostHogGraphicsImageRenderer.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PostHogGraphicsImageRenderer.swift; sourceTree = "<group>"; };
 		DA4FFBB42DAD5AF9006BAEEA /* PostHogIdentityTests.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PostHogIdentityTests.swift; sourceTree = "<group>"; };
 		DA52CACA2F24027500305F3D /* PostHogMulticastCallback.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PostHogMulticastCallback.swift; sourceTree = "<group>"; };
 		DA52CAD22F2402E000305F3D /* PostHogMulticastCallbackTest.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PostHogMulticastCallbackTest.swift; sourceTree = "<group>"; };
@@ -1334,6 +1336,7 @@
 				69F518112BAC783300F52C14 /* CGColor+Util.swift */,
 				69F518132BAC7F4300F52C14 /* Date+Util.swift */,
 				69F518152BAC7F9200F52C14 /* UIView+Util.swift */,
+				ARPERF0003000000000003 /* PostHogGraphicsImageRenderer.swift */,
 				69F518172BAC80A300F52C14 /* String+Util.swift */,
 				DA30AE682D3EFB4F00465A64 /* Optional+Util.swift */,
 				69F518192BAC81FC00F52C14 /* UITextInputTraits+Util.swift */,
@@ -2250,6 +2253,7 @@
 				6926DA8E2ADD2876005760D2 /* PostHogContext.swift in Sources */,
 				690FF0AF2AEB9C1400A0B06B /* DateUtils.swift in Sources */,
 				69F518162BAC7F9200F52C14 /* UIView+Util.swift in Sources */,
+				ARPERF0004000000000004 /* PostHogGraphicsImageRenderer.swift in Sources */,
 				69261D192AD9673500232EC7 /* PostHogBatchUploadInfo.swift in Sources */,
 				DAC699EC2CCA73E5000D1D6B /* ForwardingPickerViewDelegate.swift in Sources */,
 				DA26419C2CC0499300CB427B /* PostHogAutocaptureEventTracker.swift in Sources */,

@@ -10,6 +10,9 @@
     import Foundation
     import UIKit
 
+    // Pre-computed hex character lookup for fast color string formatting
+    private let hexChars: [Character] = Array("0123456789ABCDEF")
+
     extension CGColor {
         func toRGBString() -> String? {
             // see dicussion: https://github.com/PostHog/posthog-ios/issues/226
@@ -23,11 +26,17 @@
                 return nil
             }
 
-            let red = Int(components[0] * 255)
-            let green = Int(components[1] * 255)
-            let blue = Int(components[2] * 255)
+            let r = min(255, max(0, Int(components[0] * 255)))
+            let g = min(255, max(0, Int(components[1] * 255)))
+            let b = min(255, max(0, Int(components[2] * 255)))
 
-            return String(format: "#%02X%02X%02X", red, green, blue)
+            // Build hex string directly — avoids String(format:) overhead
+            return String([
+                "#",
+                hexChars[r >> 4], hexChars[r & 0xF],
+                hexChars[g >> 4], hexChars[g & 0xF],
+                hexChars[b >> 4], hexChars[b & 0xF],
+            ])
         }
     }
 #endif
@@ -0,0 +1,74 @@
+#if os(iOS)
+
+    import UIKit
+
+    /// Cached device RGB color space — avoids creating a new one per render call.
+    private let deviceRGBColorSpace = CGColorSpaceCreateDeviceRGB()
+
+    /// High-performance image renderer that bypasses `UIGraphicsImageRenderer`'s overhead.
+    ///
+    /// Based on Sentry's approach: directly allocates a `CGContext` with `malloc`, avoiding
+    /// UIKit's internal caching and context management abstractions.
+    ///
+    /// See: https://blog.sentry.io/boosting-session-replay-performance-on-ios-with-view-renderer-v2/
+
+    final class PostHogGraphicsImageRenderer {
+        let size: CGSize
+        let scale: CGFloat
+
+        init(size: CGSize, scale: CGFloat) {
+            self.size = size
+            self.scale = scale
+        }
+
+        func image(actions: (CGContext) -> Void) -> UIImage? {
+            let pixelsPerRow = Int(size.width * scale)
+            let pixelsPerColumn = Int(size.height * scale)
+            let bytesPerPixel = 4 // RGBA
+            let bytesPerRow = bytesPerPixel * pixelsPerRow
+            let bitsPerComponent = 8
+
+            guard pixelsPerRow > 0, pixelsPerColumn > 0 else {
+                return nil
+            }
+
+            // Allocate memory for raw image data.
+            // Using malloc instead of calloc — drawHierarchy overwrites the entire buffer,
+            // so zero-initialization is unnecessary and wastes time for large buffers.
+            let bufferSize = pixelsPerColumn * bytesPerRow
+            guard let rawData = malloc(bufferSize) else {
+                return nil
+            }
+            defer {
+                free(rawData)
+            }
+
+            guard let context = CGContext(
+                data: rawData,
+                width: pixelsPerRow,
+                height: pixelsPerColumn,
+                bitsPerComponent: bitsPerComponent,
+                bytesPerRow: bytesPerRow,
+                space: deviceRGBColorSpace,
+                bitmapInfo: CGImageAlphaInfo.premultipliedLast.rawValue
+            ) else {
+                return nil
+            }
+
+            // UIKit coordinate system is flipped vs CoreGraphics — shift and scale to match
+            context.translateBy(x: 0, y: size.height * scale)
+            context.scaleBy(x: scale, y: -1 * scale)
+
+            // Push context so drawHierarchy draws into our context
+            UIGraphicsPushContext(context)
+            actions(context)
+            UIGraphicsPopContext()
+
+            guard let cgImage = context.makeImage() else {
+                return nil
+            }
+            return UIImage(cgImage: cgImage, scale: scale, orientation: .up)
+        }
+    }
+
+#endif